Surface Morphology and Growth of Anodic Titania Nanotubes Films: Photoelectrochemical Water Splitting Studies

Abstract

Design and development of one-dimensional nanoarchitecture titania (TiO) assemblies have gained significant scientific interest, which have become the most studied material as they exhibit promising functional properties. In the present study, anodic TiO2films with different surface morphologies can be synthesized in an organic electrolyte of ethylene glycol (EG) by controlling an optimum content of ammonium fluoride (NH4F) using electrochemical anodization technique. Based on the results obtained, well-aligned and bundle-free TiO2nanotube arrays with diameter of 100 nm and length of 8 µm were successfully synthesized in EG electrolyte containing ≈5 wt% of NH4F for 1 h at 60 V. However, formation of nanoporous structure and compact oxide layer would be favored if the content of NH4F was less than 5 wt%. In the photoelectrochemical (PEC) water splitting studies, well-aligned TiO2nanotubular structure exhibited higher photocurrent density of ≈1 mA/cm2with photoconversion efficiency of ≈2% as compared to the nanoporous and compact oxide layer due to the higher active surface area for the photon absorption to generate more photo-induced electrons during photoexcitation stage.

In situ investigations of the phase change behaviour of tungsten oxide nanostructures

“…Raman spectroscopy is a more effective technique than XRD in revealing structure transitions of the complex WO x system, as Raman spectroscopy has higher sensitivity to changes in the positions of and bonding between the W and O atoms in the crystal lattice, while with XRD it is often difficult to distinguish the similar and often overlapping diffraction peaks. Using Raman spectroscopy, Lai [17] has investigated the structural change of WO 3 nanoplatelet films containing different amounts of ammonium fluoride and related it to the photocatalytic properties. Lu et al [18] have reported the oxidation and phase transition of sub-stoichiometric W 18 O 49 nanowires using intrinsic Raman spectroscopy by changing the input laser power.…”

Visible-Light Active Titanium Dioxide Nanomaterials with Bactericidal Properties

“…The pores grow into tubular features and form TNT arrays as the anodizing process continues to its final stage (Figure 12c,d). The growth of TNT arrays is described as the competition between electrochemical oxide formation and chemical dissolution of oxide by F − ions of sufficient concentrations [222][223][224]. Figure 13a,b shows the formation of TNT arrays by anodizing Ti in a mixed ethylene glycol/NH 4 F and water solution [223,225].…”

High-Performance pH Sensor Electrodes Based on a Hexagonal Pt Nanoparticle Array-Coated Nanoporous Alumina Membrane

“…Fabricating nanostructures with good alignment and uniform size to actualize most of the proposed applications by the conventional lithographic process was even more difficult [ 6 ]. Various experiments have been conducted to create porous materials using naturally occurring materials or self-organizing materials such as carbonates [ 7 , 8 , 9 , 10 , 11 ]. Porous anodic alumina membranes (PAAMs), which are incredibly porous and have specified shapes and sizes, are one sort of ordered porous structure [ 12 , 13 ].…”